Protective coating composition for metals



Patented Dec. 3, 1940 2,223,458 PROTECTIVE C'OAB'IEI G COMPOSITION FOR ALS Edward A. Nill, Highland Park, Mich., assignor to The H. A. Montgomery Company, Detroit, Mich., a. corporation of Michigan No Drawing. Application June 18, 1937, Serial No. 148,959

Claims.

This invention relates to protective coatings for metals and more particularly to rustproofing composition suitable for the protection of sheets, bars, tubes, castings, and other metal articles in factories during intervals between fabricating operations.

The object of the present invention is to provide an inexpensive material for use in providing protecting coatings for metal articles which will effectively protect the articles against the destructive action of air and moisture, which can be quickly and easily washed off when desirable for further processing of the metal articles.

a A further object is to provide a composition which can be quickly and easily applied to the metal articles by means of rolls or brushes or by spraying or dipping. The composition of the present invention consists of a base which is soluble in mineral oils, and a quantity of light mineral oil or of a mixture of light and heavy mineral oils sufficient to provide a liquid of a consistency such that it will form a thin film upon the metal to be protected. A considerable proportion of the liquid composition evaporates after application to the metal to leave a thin jellylike film on the metal surface which protects the metal surface against the action of air and moisture. 3 The base employed is a solution of a water insoluble soap such as calcium soap in a fatty acid anilid which is liquid at room temperatures. The anilid soap solution is mixed with a light mineral oil, such as kerosene or a mixture of light and heavy oils such as kerosene and parafiin oil to provide a liquid which will form a thin unbroken film on the surface of the metal to be protected.

The liquid anilid is preferably made from sperm oil. In making the anilid the glycerides 40 are first removed from the sperm oil and the fatty acid compounds in the oil are then converted into fatty acids by a suitable method such as the Twitchell process. The resulting product contains a mixture of high fatty acids calculated as about 63% oleic.

This product is reacted with aniline until no free acid is left. The resulting composition which is liquid at ordinary room temperatures is hereinafter referred to as sperm anilid. The calcium soap which is added to the sperm anilid to make the product of the present invention is preferably a calcium sperm oil soap, The soap is made by adding the required amount of caustic soda to sperm oil and boiling until saponification is completed, The saponified oil is mixed with an amount of water to make a to soap solution. The calculated amount of calcium chloride is added to convert the sodium soap in solution into calcium sperm oil soap. The water is drawn off and the precipitate is washed until it is free from chlorides, and then dried. The resulting calcium sperm oil soap is insoluble in water and also insoluble in mineral oil.

Equal parts of the calcium sperm soap and sperm anilid are mixed together and the soap dissolves in the liquid sperm anilid forming a liquid which is viscous and cloudy at room temperatures. This liquid is readily soluble in mineral oils and a small percentage of the anilid soap solution added to a light mineral oil, such as kerosene or a mixture of light and heavy oils, provides a liquid composition suitable for forming protective coatings on metal. The evaporation of the lighter constituents of the oil after application to the metal surface leaves a thin jellylike film over the entire surface of the metal which effectively protects the metal against air and moisture. 3% of the anilid solution with a mixture of 50% kerosene and 47% parafiin oil has been found to be an excellent composition for rust proofing ferrous metals. The proportion of light oil and heavy oil in the composition may be varied considerably. Kerosene alone may be used and the amount of volatile constituent in the liquid will determine the consistency of the film which is left upon the metal surface,

Various fatty acid anilid compositions may be employed which are liquids soluble in mineral oil and various calcium or other water insoluble metallic soaps such as aluminum, manganese, lead, iron or copper soaps may be employed. For example, the anilids and calcium soap of castor oil may be employed.

Furthermore, it is to be understood that the particular composition described, and the particular procedure set forth, are presented for pur poses of explanation and that various modifications of said composition and procedure can be made without departing from my invention as defined in the appended claims.

What I claim is:

1. A base for metal protective coatings comprising a solution of a metallic sperm oil soap, which is insoluble in water, in sperm anilid. 5

2. A' metal protecting composition comprising a solution of a metallic sperm oil soap which is insoluble in water in sperm anilid mixed with mineral oil.

3. A metal protecting composition comprising 5 a mineral oil having dissolved therein a film 5. A metal protecting composition comprising a stiffening :base consisting of substantially equal mineral oil having dissolved therein a film stiffenparts of a metallic sperm oil soap which is insoluing base consisting of substantially equal parts of ble in water, and sperm anilid. calcium sperm oil soap and sperm anilid.

4. A metal protecting composition comprising a solution of calcium sperm oil soap and sperm ani- EDWARD A. NILL.

lid in mineral oil. 

